"It's certainly a positive sign that African-American youth are getting the message," he told Shots.

He cites another new piece of evidence that black teens are more HIV-aware: Many of them are getting tested for the virus.

"Overall, about 13 percent of high school students have ever been tested for HIV," says study coauthor Laura Kann of the CDC. "Black students are far more likely, at 24 percent, to have been tested. [That suggests] more of them have gotten the message about the importance of testing."

But the picture is not all positive. "Condom use is decreasing among this population," Kann says, "and that kind of balances the good news."

The use of condoms has been dropping among all high-schoolers, including African-Americans.

That presents a puzzle. If black teens are getting the message about the risks of early sex and many sex partners, why aren't they getting the message about using condoms?

Kann says she doesn't know. "It's sure a point of concern at this point, and one that we're very interested in reversing," she told Shots.

Other research presented at the AIDS meeting raises an even bigger concern. Preliminary results from a six-city study of gay or bisexual young adult black men shows a lot of risky behavior. Study authors say these men are part of "an evolving concentrated epidemic."

The study "clearly shows that young men who have sex with men or who identify as gay or bisexual have far higher rates of a wide range of health risk behaviors, not just sexual risk behaviors," Kann says.

This is a paradox. While the risk of getting HIV has been going down among black high-schoolers, it's still high among their immediate elders. That's true among young black adults in general, and it's especially true of young blacks who are gay and bisexual.

Fenton thinks he knows why. "What is happening is that we are seeing these positive trends, but these positive trends may not be enough to offset high levels of HIV and sexually transmitted diseases within the black community," he says.

In other words, even if black high-schoolers are getting the message about safer sex, they're graduating into a very risky world.

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Transcript

AUDIE CORNISH, HOST:

From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.

ROBERT SIEGEL, HOST:

And I'm Robert Siegel.

Today at the International AIDS Conference here in Washington, new research was presented about the problem of HIV among African-Americans. Washington has the highest rate of HIV of any city in America and African-Americans have been especially hard hit. We'll hear more about that in a moment. First, the new data from the Centers for Disease Control and Prevention show that black teens are engaging in far less risky sexual behavior than 20 years ago.

Here's NPR's Richard Knox.

RICHARD KNOX, BYLINE: African-American teenagers are the next generation in a community that's the hardest hit by HIV in the nation. So it's significant that they're lowering their risk of getting the virus. Here's what the new study shows about their risky behavior.

The percentage of black high-schoolers who've ever had sex has dropped over the past 20 years, from 82 percent to 60 percent. And there's a big drop in black teens who've had multiple sex partners. In 1991, 43 percent had. Now it's about half that.

Dr. Kevin Fenton says this is evidence that black high-schoolers are more aware of HIV risks. Fenton is the CDC's top AIDS official.

KNOX: He believes that because of another new piece of evidence that shows their awareness of the link between HIV and sex. Here's study co-author Laura Kann of the CDC.

LAURA KANN: Overall, about 13 percent of high schools students have ever been tested for HIV. Black students are far more likely, at 24 percent, to have ever been tested for HIV.

KNOX: That suggests what?

KANN: That more of them have gotten the message about the importance of testing.

KNOX: But the picture is not all positive.

KANN: Condom use is decreasing among this population. That kind of balances the good news.

KNOX: The use of condoms has been dropping among all high-schoolers, including African-Americans. That presents a puzzle. If black teens are getting the message about the risks of early sex and many sex partners, why aren't they getting the message about using condoms? Laura Kann says she doesn't know.

KANN: It's sure a point of concern at this point and one that we're very interested in reversing.

KNOX: And other research this week raises an even bigger concern. A big study of young black men who are gay and bisexual - this time young adults, not teens - shows a lot of risky behavior.

KANN: It clearly shows that young men who have sex with men in high school, or who identify as gay or bisexual in high school, have far higher rates of a wide range of health risk behaviors, not just sexual risk behaviors.

KNOX: This is a paradox. The risk of getting HIV has been going down among black high-schoolers, but is still high among young adults. That's true among young black adults in general, and it's especially true of young blacks who are gay and bisexual.

Here's Kevin Fenton again.

FENTON: What is happening is that we are seeing these positive trends. But these positive trends may not be enough to offset high levels of HIV and STDs within the black community.

KNOX: So even if black high-schoolers are getting the message about safer sex, they're graduating into a very risky world.